It is known to use a fluid flow control valve in an automotive cooling system to regulate the flow of coolant and thereby regulate the operating temperature of the engine of the automobile.
One class of conventional fluid flow control valves for automotive cooling systems employs a wax element that is sensitive to coolant temperature to regulate the opening and closing of the fluid flow control valve thereby regulating the flow of coolant through the automotive cooling system. However, due to the nature of the wax element, this type of system is slow to respond to changes in the temperature of the engine. Furthermore, since the opening and closing of the valve is controlled by the thermal properties of the wax used in the valve, the operating temperature range in which the engine is controlled cannot be easily adjusted.
Other systems employ temperature sensors that are used to detect the temperature of the engine. The fluid flow control valve is then regulated based on the sensed temperature of the engine using a valve that is electrically-driven, for example, by a stepper motor. While these systems respond quickly to changing engine temperature, the electrically-operated valves employed in these systems are prohibitively expensive.
In some automobiles, it may be necessary to operate the engine of the automobile in different temperature ranges depending upon an operating mode of the automobile. For example, in flex-fuel vehicles, which include engines adapted to use two or more different types of fuel, the different types of fuel burn at different temperatures, and thus, the operating temperature range of the engine must be adjusted based on the type of fuel. However, known systems have not provided a practical means by which the temperature range in which the engine is regulated may be changed in response to an operating mode of the engine.
It would be desirable to have an inexpensive, electrically-operated temperature control valve for an automotive cooling system that provides good response characteristics, is inexpensive, and allows the temperature range of the engine to be changed based on an operating condition of the engine.